Arduino remote car starter! :)

Hey guys, So it has been over 2 years since the last time I messed with an Arduino. My last project was a RGB led controller for my custom pc with custom software to control it. Lots of fun. Anyways I’m a bit rusty and have been sort of refreshing myself on it.

Anyways, I had an idea of making a remote starter for my car on the cheap compared to viper or add-on units going for $60+. Don’t forget the installing fee too. I didn’t want to have to carry a second remote as I like to have little as possible on my key chain. Plus I like DIY and tinkering with stuff.

My plan is to use the factory remote as it has three buttons. Master unlock/lock, All unlock, and Headlight switch. I plan on using the signal from the alarm to turn on the headlights as an interrupt for the Arduino to wake up and then wait for me to unlock all doors to start the remote start process. I have a basic knowledge of how to go about this. I have all the main wires I need mapped out but I ran into a problem of when the alarm is disarmed it also sends a signal to the headlights to turn on. I feel would confuse the Arduino and make it start the car whenever I unlock/disarm the car. I don’t want that.

Can the Arduino sense double pulse inputs somehow so that it knows if I press the headlight button on the fob twice, once to wake the Arduino from sleep and then the second pulse to check if all doors have been unlocked.

If anyone has other ideas or an idea how I would go about this please help thanks in advance! Sorry for the long post. Wanted to make sure I get my info across correctly.

P.S. The doors all unlock with a double pulse from the alarm if ground is sent to the locks twice within 2 seconds. I also have the wiring diagrams if needed.